Journal article

Demographic collapse and low genetic diversity of the Irrawaddy dolphin population inhabiting the Mekong River

Michael Krutzen, Isabel Beasley, Corinne Y Ackermann, Dietmar Lieckfeldt, Arne Ludwig, Gerard E Ryan, Lars Bejder, Guido J Parra, Rebekka Wolfensberger, Peter BS Spencer



In threatened wildlife populations, it is important to determine whether observed low genetic diversity may be due to recent anthropogenic pressure or the consequence of historic events. Historical size of the Irrawaddy dolphin (Orcaella brevirostris) population inhabiting the Mekong River is unknown and there is significant concern for long-term survival of the remaining population as a result of low abundance, slow reproduction rate, high neonatal mortality, and continuing anthropogenic threats. We investigated population structure and reconstructed the demographic history based on 60 Irrawaddy dolphins samples collected between 2001 and 2009. The phylogenetic analysis indicated reciprocal..

View full abstract

University of Melbourne Researchers


Funding Acknowledgements

The authors would like to thank Gordon Congdon (WWF-Greater Mekong Program) for his significant contribution to Mekong dolphin research and conservation efforts, and Verne Dove for her assistance with the stranding program and collection of samples used in this analysis. Many thanks to Martin Gilbert (WCS-Cambodia Program) who managed the Cambodian stranding program from 2005-2007. IB would like to thank the funding organisations that supported the Mekong Dolphin Conservation Project from 2001-2007; Ocean Park Conservation Foundation Hong Kong, the Mekong River Commission Environment program, Rufford Foundation Small Grants Program, Society for Marine Mammalogy Small Grants Program, IUCN Mekong Wetlands Biodiversity Project, James Cook University and the Wildlife Conservation Society Research Fellowship Program. DL and AL thank Petr Obrdlik (sample organisation) and the WWF Germany (financial support). Thanks to all the Cambodian staff and volunteers that assisted to collect samples and conduct necropsies, particularly Lor Kim San, Phay Somany, Sean Kin and Department of Fisheries officers. Our deepest gratitude and thanks to all local villagers throughout the lower Mekong River for their generous hospitality, assistance with reporting and recovering numerous carcasses, and sharing their knowledge about the area and the Mekong dolphin population.